Explosion-proof-cartridge cut-out.



W. KLEMENT.

EXPLOSION PROOF CARTRIDGE GUT-OUT.

APPLICATION FILED AUG. 5, 1910.

1,007,876, Patented Nov. 7, 1911.

. I, "I: 4 0 1; 1 //71/e hh; n i mm? S h r/h e /m hlemufl 4y llsaffar-rw s UNITED STATES PATENT OFFICE,

WILHELM KLEMENT, 0F N EU-FINKENKRUG-FALKENHAIN, GERMANY, ASSIGNOR T0SIEMENS-SCHUCKERTWERKE G. M. B. 11,, OF BERLIN, GERMANY, A CORPORATION0F GERMANY.

T 0 all whom it may concern:

Be it known that I, VVILHELM KLEMENT, a subject of the German Emperor,and residing at Neu-FinkenkrugFalkenhain,-Germany have invented certainnew and useful- Improvements in EXplosion-Proof-Cartridge Cut-Outs, ofwhich the following is a specification.

My invention relates to explosion-proof cartridge cut-outs having aplurality of fuses of various lengths connected in parallel.

In order to prevent the occurrence of an arc at the contacts of thefusible strips in the well-known open strip fuses it has been founoadvantageous to arrange in parallel with the principal fusible strip anauxiliary fusible wire of greater length and greater resistance whichonly carries a relatively small part of the current when the fuse isbeing used, but. carries the entire current immediately after the mainfusible strip has been destroyed. By applying this arrangement known inopen fusible cut-outs to perfectly closed cartridges comprising fusiblefilaments and granular filling considerable advantages'are obtained withregard to the cartridge cut-outs and their action. In the closedcartridge cut-outs the length and section of the fusible filamentsmustalso be such that only a small portion of the total current is carriedby the long fusible filaments.

'When the electrical proportions of the main and auxiliary fusiblefilaments of closed cut-outs are correctly selected, the distancebetween the contacts for the short filaments can be made relatively verysmall on the one hand by embedding the fusible filaments in anindifferent filling material on the other hand by providing a. fireproofclosure between the places where the filaments are attached to thecontacts for protection against the flame, and, lastly, by completelyclosing the entire cartridge. By shortening the length of the filamentsin this manner the certainty of action of the cartridge is increased inconsequence of its being possible to diminish the requisite masses ofmetal. These advantages can only be obtained, however. when, accordingto my invention, the fusible filaments of various length located in acommon fuse chamber are separated in such a manner from one another byinsulating material that the flame of the long filaments does not bridgeover the contacts of Specification of Letters Patent.

EXPLOSION-PROOF-CARTRIDGE CUT-OUT.

Patented Nov. 7, 1911.

Application filed August 5, 1910. Serial No. 575,820. i

the short filaments and thereby cause a permanent are. I may separatethe fusible filaments either by the filling material itself or by aspecial partition.-

The arrangement of the long fusible filaments in a special closed fusechamber within the fuse insertion carrying the short fusible filamentsis particularly advantageous.

Several illustrative embodiments of my invention are represented by wayof example in the accompanying drawing, wherein Figure 1 is a plan ofacartridge having end contacts, and Fig. 2 shows the same incross-section; Fig. 3 shows a cartridge in the form of a strip 'in plan,the covering plates having been removed, and Fig. 4 shows thelattercartridge in longitudinal section.

Referring firstly to Figs. 1 and 2, eight short fusible filaments bare.stretched between the pot-shaped recessed connecting members a. \Vithinthe body 0 of the car-- tridge is a special small tube 6 containing thelong auxiliaryfilament (Z. The entire body, including the small tube e,is covered by end contacts 70 which. are electrically connected with themetal pots a and the ends of the wire d. The fuse chambers f and g areprovided in known manner with granular damping material, and aresecurely-closed from the outside by fireproof stoppers 72.

In the strip-shaped cartridge according to Figs. 3 and 4 the shortfusible filaments b, and the long tensioned wires d, are stretchedbetween the contact blades h, h. To-this end, the contact blades haveinwardly-directed lugs s so that distance between parts of the blades islong and that between other parts is short. The two groups of fuses ofdifferent length are separated by a fireproof partition n. In thisarrangement also the places at which the fuses are connected to thecontacts are protected by fireproof stoppers 7). With the exception ofthe terminal contacts the cut-out is covered by stiffening closureplates 0, of" insulating material and the fuse chamber filled withgranular damping material.

I claim 1. In a cartridge cut out, the combination with anexplosion-proof cartridge having terminal contacts; of a plurality offusible filaments of various lengths connested in parallel between saidcontacts, the total resistance of the shorter filaments being smallerthan the total resistance of the longer filaments.

2. In a cartridge cut-out, the combination with a closed cartridgehaving terminal contacts 0f a plurality of fusible filaments of variouslengths connected in parallel between the contacts, the total resistanceof the shorter filaments being smaller than the total resistance of thelonger filaments, and

insulating means between the shorter filaments and the longer forpreventing the flame of the longer filaments touching the contacts ofthe previously fused shorter filaments.

3. In a cartridge cut-out, the combination with a closed cartridgehaving terminal contacts of a plurality of fusible filaments of variouslengths connected in parallel between the contacts, the total resistanceof the shorter filaments being smaller than the total resistance of thelonger filaments, and solid insulating means between the shorterfilaments and the longer for preventing the flame of the longerfilaments touching the contacts of the previously fused shorterfilaments.

4. Ina cartridge cut-out, the combination with a closed cartridge havingterminal contacts of a plurality of fusible filaments of tween thecontacts, the total resistance of the shorter filaments being smallerthan the total resistance of the longer filaments, and a solidinsulating partition between the shorter filaments and the longer forpreventing the flame of the longer filaments touching the contacts ofthe previously fused shorter filaments.

5. In a cartridge cut-out the combination with a closed cartridge havingterminal contacts of .a plurality of fusible filaments of variouslengths connected in parallel between the contacts, the total resistanceof the shorter filaments being smaller than the total resistance of thelonger filaments, and a tubular insulating'partition between the shorterfilaments and the longer, for preventing the fiame of the longerfilaments touching the contacts of the previously fused shorterfilaments.

In testimony whereof I have signed my name to this specification in thepresence of two witnesses.

WILHEL KLEMENT! Witnesses WOLDEMAR HAUr'r, HENRY l lasrnn.

